Liquid crystal display devices are widely used for display equipment of TVs, PCs, PDAs, and the like as they advantageously have a thin profile, light weight, and low power consumption. Especially, the size of liquid crystal display devices has rapidly increased in recent years, as typically shown in the case of liquid crystal display devices for TVs. For producing larger liquid crystal display devices, the MVA (Multi-domain Vertical Alignment) mode is favorably employed in which a large-sized display device having a wide view angle can be produced at a high yield. In the MVA mode, since liquid crystal molecules are aligned perpendicularly to a substrate face when no voltage is applied to a liquid crystal layer, the contrast ratio is higher than that of the conventional TN (Twisted Nematic) mode.
In the MVA mode, an alignment film does not control the tilt direction of liquid crystal molecules. The tilt direction of liquid crystal molecules is determined by protrusions (ribs) formed of insulating materials and/or slits of electrodes. Accordingly, alignment treatment on an alignment film is not needed, avoiding generation of static electricity and dusts by rubbing or the like. In such a case, cleaning treatment is not needed after formation of the alignment film. In addition, the initial tilt of liquid crystal molecules is less varied, which is effective in simplification of the production process, improvement in the yield, and cost reduction.
In the MVA mode, however, the alignment film itself is needed though the alignment treatment is not needed. More preferably, the alignment film is not formed, in consideration of the influence on the alignment of liquid crystal molecules given by the nonuniformity in the film thickness and contamination of the alignment film, and an increase in the production steps for forming the alignment film and investment for facilities.
To solve the above problem, a technique having been developed recently is forming an alignment control layer by enclosing a liquid crystal composition containing liquid crystals and polymerizable components such as monomers and oligomers (hereinafter, abbreviated as monomers and the like) between substrates, and polymerizing the monomers and the like (see Patent Literatures 1 and 2). Such an alignment control layer allows control of the alignment of liquid crystal molecules without an alignment film. The technique of controlling the alignment of liquid crystal molecules using, not an alignment film, an alignment control layer is also referred to as the alignment filmless technique.